Total Synthesis of Citreochlorol Monochloro Analogs via a Catalytically Enantioselective Carbonyl Allylation

Synthesis ◽  
2021 ◽  
Author(s):  
Cheng-Kun Lin ◽  
Bing-Han Hsieh ◽  
Chun-Fu Wu
Keyword(s):  
Secondary Metabolites ◽  
Total Synthesis ◽  
Synthetic Route ◽  
Epoxide Opening ◽  
Key Features ◽  
Carbonyl Allylation

An efficient synthetic route to citreochlorol analogs, halogenated polyketide secondary metabolites, is described. The key features are Krische's enantioselective carbonyl allylation, IBr-promoted cyclization, and regioselective epoxide opening. The importance of the route lies in the access of the versatile epoxy ether 14, which opens access to the citreochlorol monochloro derivatives 5 and 6.

scholarly journals Anabaenopeptins: What We Know So Far

Toxins ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 522
Author(s):  
Patrick Romano Monteiro ◽  
Samuel Cavalcante do Amaral ◽  
Andrei Santos Siqueira ◽  
Luciana Pereira Xavier ◽  
Agenor Valadares Santos
Keyword(s):  
Secondary Metabolites ◽  
Bioactive Compounds ◽  
Inhibitory Activity ◽  
Important Class ◽  
Biotechnological Applications ◽  
Peptide Synthetases ◽  
Ecological Roles ◽  
Cyclic Hexapeptides ◽  
Key Features

Cyanobacteria are microorganisms with photosynthetic mechanisms capable of colonizing several distinct environments worldwide. They can produce a vast spectrum of bioactive compounds with different properties, resulting in an improved adaptative capacity. Their richness in secondary metabolites is related to their unique and diverse metabolic apparatus, such as Non-Ribosomal Peptide Synthetases (NRPSs). One important class of peptides produced by the non-ribosomal pathway is anabaenopeptins. These cyclic hexapeptides demonstrated inhibitory activity towards phosphatases and proteases, which could be related to their toxicity and adaptiveness against zooplankters and crustaceans. Thus, this review aims to identify key features related to anabaenopeptins, including the diversity of their structure, occurrence, the biosynthetic steps for their production, ecological roles, and biotechnological applications.

scholarly journals A concise enantioselective synthesis of the guaiane sesquiterpene (−)-oxyphyllol

2013 ◽  
Vol 9 ◽  
pp. 2028-2032 ◽  
Author(s):  
Martin Zahel ◽  
Peter Metz
Keyword(s):  
Total Synthesis ◽  
Enantioselective Synthesis ◽  
Englerin A ◽  
Epoxide Opening

(−)-Oxyphyllol was prepared in only 4 steps from an epoxy enone that already served as an intermediate for the total synthesis of the anticancer guaiane (−)-englerin A. A regio- and diastereoselective Co(II)-catalyzed hydration of the olefin and a transannular epoxide opening were used as the key reactions.

scholarly journals First Stereoselective Total Synthesis of Ciryneol C

SynOpen ◽  
2019 ◽  
Vol 03 (02) ◽  
pp. 59-66
Author(s):  
Ambati Sharada ◽  
Lakshmi Srinivasa Rao Kundeti ◽  
Kallaganti V. S. Ramakrishna ◽  
Kommu Nagaiah
Keyword(s):  
Total Synthesis ◽  
Coupling Reactions ◽  
Asymmetric Total Synthesis ◽  
Acetylene Derivative ◽  
Wittig Olefination ◽  
Epoxide Opening ◽  
Key Steps

The acetylene derivative Ciryneol C was isolated from the roots of C. japonicum. The asymmetric total synthesis of Ciryneol C was achieved in seven steps, with Horner–Wittig olefination, regioselective epoxide opening, and Cadiot–Chodkiewicz coupling reactions being the key steps.

Oxidative Dearomatization and Sigmatropic 1,3-Acyl Shift in Excited State: Aromatics to Embellished cis-Hydrindanes

Synthesis ◽  
2019 ◽  
Vol 51 (07) ◽  
pp. 1633-1642
Author(s):  
Vishwakarma Singh ◽  
Raghaba Sahu
Keyword(s):  
Excited State ◽  
Ring Expansion ◽  
Synthetic Route ◽  
Oxidative Dearomatization ◽  
Key Features

A stereoselective synthetic route to embellished cis-hydrindanes from simple aromatic precursors is described. Oxidative dearomatization, ring expansion, and photochemical 1,3-acyl shift are the key features of our approach. Oxidative dearomatization of o-(hydroxymethyl)phenols followed by π4s + π2s cycloaddition furnishes bicyclo[2.2.2]octanes with contiguous keto epoxide groups, which upon ring expansion lead to bicyclo[3.2.2]nonanes endowed with a β,γ-enone chromophore. Unbridging of bicyclo[3.2.2]nonanes upon singlet excitation furnishes embellished cis-hydrindanes.

Total synthesis of (±)-9-deoxygoniopypyrone. Application of the iodocyclofunctionalization reaction of bold α-allenic alcohol derivatives

1998 ◽  
Vol 76 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Richard W Friesen ◽  
Suzanne Bissada
Keyword(s):  
Total Synthesis ◽  
Primary Alcohol ◽  
Silyl Ether ◽  
Protecting Group ◽  
Acetylenic Ester ◽  
The Third ◽  
Vicinal Diol ◽  
Epoxide Opening ◽  
Vinyl Iodide ◽  
Acidic Conditions

The synthesis of ( ±)-9-deoxygoniopypyrone (1) from the α-allenic alcohol 5 is described. Iodocyclofunctionaliztion of the N-tosyl carbamate derivative of 5 using I2 and Ag2CO3 provided, in a highly diastereoselective and regioselective fashion, the vinyl iodo syn-vicinal diol 4. Two routes were explored in order to introduce the third stereogenic centre in the molecule. Reductive deiodination of the vinyl iodide and diastereoselective epoxidation of the derived acetonide14 using mCPBA provided a mixture of epoxides 15 and 16 (2:1) in which the desired threo diastereomer predominated. Alternatively, dihydroxylation of acetonide 14 (OsO4, NMO) yielded a mixture of diols 21 and 22 (2:3) which were separated after monosilylation (TBDMSCl) of the primary alcohol. The major silyl ether erythro diastereomer 24 was converted to the desired epoxide 15 by mesylation (MsCl, Et3N) and epoxide formation (TBAF) with inversion of stereochemistry. The minor threo diastereomer 23 was also converted to the desired epoxide 15 (TBAF; ArSO2Cl; NaOMe). Epoxide opening was effected with lithium acetylide and the resulting alkyne 27 was carbonylated (MeLi, ClCO2Me) to afford the α , β-acetylenic ester 28. Semi hydrogenation over Lindlar's catalyst followed by protecting- group removal under acidic conditions provided ( ±)-8-epigoniodiol 30. Finally, conversion of 30 to ( ±)-9-deoxygoniopypyrone 1 was effected under basic conditions (DBU).Key words: ( ±)-9-deoxygoniopypyrone, α-allenic alcohol, iodocyclofunctionalization, syn-diol.

Approaches to the total synthesis of triterpenes. VIII. The ABC + D/E approach. Synthesis and X-ray structure determination of 1β,4a β-dimethyl-7-methoxy-1α- (7′,7′-ethyleneketal-6′,6′-dimethyl-3′-ketooctyl)-3,4,4a,9,10,10aα-hexahydro- 2(l-H)phenanthrone

1982 ◽  
Vol 60 (4) ◽  
pp. 509-513 ◽  
Author(s):  
John W. ApSimon ◽  
Rick P. Sequin ◽  
Carol P. Huber
Keyword(s):  
Total Synthesis ◽  
Single Crystal ◽  
Structure Determination ◽  
Title Compound ◽  
Trimethylsilyl Ether ◽  
Synthetic Route ◽  
X Ray ◽  
Pentacyclic Triterpenes ◽  
Ongoing Work

The title compound was made following a projected synthetic route to pentacyclic triterpenes. The key step in the route is the alkylative trapping of the enolate derived from the enol trimethylsilyl ether 8. The stereochemical consequence of this reaction is confirmed by a single crystal X-ray structure determination on 4, which although of no further utility in the projected synthesis, nevertheless served as a useful template for this determination. In this way, ongoing work in a parallel series of compounds rests on a firm stereochemical footing.

ChemInform Abstract: A New Synthetic Route of 2-Aroyl- (IV) and 2-Benzyl-benzofurans (V) and Their Application in the Total Synthesis of a Metabolite (VI) Isolated from Dorstenia gigas.

ChemInform ◽  
2009 ◽  
Vol 40 (20) ◽  
Author(s):  
Christian Correa ◽  
Maria del Carmen Cruz ◽  
Fabiola Jimenez ◽  
L. Gerardo Zepeda ◽  
Joaquin Tamariz
Keyword(s):  
Total Synthesis ◽  
Synthetic Route

Golden opportunities in catalysis

2008 ◽  
Vol 80 (5) ◽  
pp. 1063-1069 ◽  
Author(s):  
Norbert Krause ◽  
Volker Belting ◽  
Carl Deutsch ◽  
Jörg Erdsack ◽  
Hong-Tao Fan ◽  
...  
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
High Reactivity ◽  
Donor Ligands ◽  
Cyclization Product ◽  
Chirality Transfer ◽  
Key Features ◽  
Stereogenic Center

The gold-catalyzed endo-cycloisomerization of allenes bearing nucleophilic substituents in the α- or β-position opens up a versatile access to various five- and six-membered heterocycles. Key features of these transformations are the high reactivity of the allene in the presence of Lewis-acidic, carbophilic gold(I) or gold(III) catalysts, and the chirality transfer from the allenic axis of chirality to the new stereogenic center in the cyclization product. Recent contributions of our group include the optimization of chirality transfer by using σ-donor ligands to gold, and applications in the total synthesis of natural products, e.g., of the β-carboline alkaloids (-)-isocyclocapitelline and (-)-isochrysotricine.

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